An integrated feasibility study using passive geophysical methods for the investigation of the Gerolekas bauxite deposits site, Greece. Issue 6 (3rd December 2021)

• Record Type: Journal Article
• Authors: Orfanos, C.; Leontarakis, K.; Polychronopoulou, K.; Apostolopoulos, G.; Athanasas, K.; Martakis, N.
• Other Names: Zhdanov Michael S. guestEditor.; Apostolopoulos George guestEditor.; DiFrancesco Dan guestEditor.
• Is Part Of: Near surface geophysics. Volume 20:Issue 6(2022)
• Page Start: 607
• Page End: 622
• Publication Date: 2021-12-03
• Subjects: 3D -- electromagnetic -- gravity -- integration -- seismic; Earth (Planet) -- Surface -- Periodicals; Geophysics -- Technique -- Periodicals; Engineering geology -- Periodicals; Geophysics -- Periodicals; Planets -- Surfaces; Engineering geology; Geophysics -- Technique; Geophysics; Earth (Planet); Periodicals; 550
• DOI: 10.1002/nsg.12181
• Languages: English
• ISSNs: 1569-4445

Abstract

ABSTRACT: The scope of this research is to delineate an optimized strategy for the implementation of cost‐effective and environmentally friendly passive geophysical methods in a challenging environment, in this case the Gerolekas bauxite mines, Greece. In this region, bauxite deposits have been detected and are being exploited at the interfaces between limestone layers in the autochthonous zone of Parnassus–Giona. The area under investigation, Gerolekas, is an allochthonous overthrust zone that overlays a part of the autochthonous geological structure. Currently, there is no information about the possible continuation of the bauxite deposits under Gerolekas below a certain depth. In this study, an integrated multi‐parameter approach using gravity, magnetotelluric and passive seismic methodologies is evaluated through a feasibility study incorporating realistic synthetic data. The specific strategy involves building a lithological model of the area by exploiting more than 4000 boreholes and incorporating data from in situ geological observations and official geological mapping. The 3D lithological model is then converted to equivalent geophysical models, based on in situ measurements, both on the surface and inside the mining galleries, as well as on data from previous studies in the literature, which together serve as the basis for the inversion procedures. The feasibility study is applied, simulating two different extreme realistic scenarios, by adding synthetic boreholes to the real ones, setting the optimum parameterization to control any possible scenario to be resolved, and evaluating the contribution of a priori information, to create starting models. Finally, a multi‐parameter analysis is formulated and applied to all inverted models to create a litho‐constrained unified geophysical model, providing an unbiased, integrated, statistically driven model of the area and generating updated geophysical models that are significantly improved.